Lime production

Heating limestone gives burnt lime (calcium oxide) in the form of lump lime:

CaCO3 + heat => CaO + CO2

Although the reaction can take place at temperatures around 900°C, the firing temperature in shaft kilns is held between 1000 and 1100 °C to ensure the complete decomposition of the calcium carbonate whilst maintaining consistently high reactivity in the burnt lime.

Both heavy-oil fired shaft kilns currently in use at KFN run almost non-stop, i.e. limestone is constantly fed into the kilns from the top whilst lump lime is delivered non-stop from the bottom. Lump lime is marketed principally to the steel industry; lump lime is also ground to make fine white lime or slaked to produce hydrated lime.